Method of forming a component module

ABSTRACT

A method of forming a component module is disclosed. A base is provided, the base being electrically conductive. An insulative layer is also provided on the base, with a first area being substantially free of the insulative layer. First and second traces are provided on the insulative layer adjacent the first area, with these traces extending therefrom. A die is positioned on the first area and electrically connected to the first and second traces. Finally, a protective layer is provided over the die.

RELATED APPLICATIONS

This application claims priority to U.S. application Ser. No.15/822,574, filed Nov. 27, 2017, now U.S. Pat. No. 10,100,982, which isa continuation of U.S. application Ser. No. 14/913,627, filed Feb. 22,2016, now U.S. Pat. No. 9,829,159, which is a national phase of PCTApplication No. PCT/US2014/052336, filed Aug. 22, 2014, which in turnclaims priority to United States Provisional Application No. 61/869,367,filed Aug. 23, 2013, each of which is incorporated herein by referencein its entirety.

TECHNICAL FIELD

This disclosure relates to the field of component modules, such as lightemitting diode (LED) modules.

DESCRIPTION OF RELATED ART

LED modules are a known way of providing illuminate with the use ofLEDs. LEDs require preparation to be useful in lighting. Existing LEDmodules include a LED array that is configured based on the type of LED.For example, chip-on-board (COB) LEDs array include LED chips that aretypically mounted on a reflective surface and electrically connectedtogether with wire-bonding. Because it is somewhat more complicated tohave and maintain a balance of red, green and blue colors so as toprovide desired light output, often it is desirable to have an efficientLED that emits a small range of wavelengths and use a phosphor toconvert the emitted wavelengths to a desirable spectrum. Thus, an LEDarray can include one or more LED chips placed on a substrate, thesubstrate which can be a metal-clad PCB or other desirable material. TheLED chips are wire bonded in a pattern that connects them to an anodeand cathode and then the chips can be covered appropriate layers ofsilicone and phosphor so as to protect the chips while providing aconversion of the light with the phosphor layer.

The resultant LED array provides top facing LEDs and also can providetop facing contacts that are electrically connected to the anode andcathode. This makes it possible to secure the LED array to a heat sinkand connect power to the contacts in a reliable manner (e.g., bypressing down on the LED array with a holder). Because of the increasingefficiency of LEDs, the LED array has become smaller and that hasresulted in the ability to offer a substrate that is reduced in size.While this would be beneficial from a cost standpoint, the reduction insize has made it more difficult to work with and secure the LED arrayinto an application (such as a fixture or bulb). One way to address thehandling problem is to use a holder to secure the LED array. A holder,which can be formed of an insulative material, can provide electricalconnection to the contacts on the LED substrate and be mounted securelyto the LED array. For example, the physical connection can be made withthe use of solder or conductive adhesive without the use of secondaryfasteners, thus the size of the LED array can be minimized and theholder (being formed of less costly materials) can provide the physicaland electrical connection between the contacts and an external powersource. An embodiment of a possible construction of an LED module soconstructed is depicted in U.S. Publication No. 2013/0176732, filed Jan.4, 2013. While such LED modules are suitable for a number ofapplications, further improvements would be appreciated by certainindividuals.

BRIEF SUMMARY

A method of forming a component module is disclosed. A base is provided,the base being electrically conductive. An insulative layer is alsoprovided on the base, with a first area being substantially free of theinsulative layer. First and second traces are provided on the insulativelayer adjacent the first area, with these traces extending therefrom. Adie is positioned on the first area and electrically connected to thefirst and second traces. Finally, a protective layer is provided overthe die.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and not limitedin the accompanying figures in which like reference numerals indicatesimilar elements and in which:

FIG. 1 illustrates a perspective view of an embodiment of a LED module.

FIG. 2 illustrates a simplified, partially exploded perspective view ofthe embodiment depicted in FIG. 1.

FIG. 3 illustrates an enlarged perspective view of the LED moduledepicted in FIG. 2.

FIG. 4 illustrates a perspective view of another embodiment of an LEDmodule.

FIG. 5A illustrates an elevated side view of a schematic representationof an embodiment of a base and light engine.

FIG. 5B illustrates an elevated side view of a schematic representationof another embodiment of a base and light engine.

FIG. 5C illustrates an elevated side view of a schematic representationof another embodiment of a base and light engine.

FIG. 5D illustrates an elevated side view of a schematic representationof another embodiment of a base and light engine.

FIG. 6 illustrates a schematic depiction of another embodiment of an LEDmodule.

FIG. 7 illustrates a method of providing an LED module.

FIG. 8 illustrates a side view of a schematic representation of asimplified embodiment of a base suitable for use with an LED module.

FIG. 9 illustrates a side view of a schematic representation of anembodiment of an LED module.

DETAILED DESCRIPTION

The detailed description that follows describes exemplary embodimentsand is not intended to be limited to the expressly disclosedcombination(s). Therefore, unless otherwise noted, features disclosedherein may be combined together to form additional combinations thatwere not otherwise shown for purposes of brevity.

FIGS. 1-3 illustrate a first embodiment of a light emitting diode (LED)module 10. The LED module 10 includes a base 15 that is conductive andincludes an insulative layer 21 provided on the base 15 in a selectivemanner. The base 15 supports a light emitting region 20, which includesLED chips 38 that are positioned in a reflective area 22. The reflectivearea 22 is preferably free of the insulative layer 21. To provide powerto the LED chips 38, conductive traces 30 a, 30 b are provided on theinsulative layer 21. The trace 30 a extends from pad 31 (which acts asan anode) to connecting region 33 and the trace 30 b extends from pad 32(which acts as a cathode) to connecting region 34. Wire bonds 35 areused to electrically connect the various LED chips 38 to the connectingregions 33, 34 in a desired pattern. As can be appreciated, the pads 31,32 are positioned on a connecting flange 17. The connecting flange 17can extend from the base 15 at an angle so as to provide access for aconnector 40, assuming the base 15 is mounted flush with a supportingsurface (not shown). As can be appreciated from FIGS. 5A-5D, theconnecting flange 17 a-17 d can be provided in a wide range ofconfigurations, such as angled up, angled down, parallel with orparallel and offset with the base 15 a-15 d. In other words, the lightemitting region 20 a, 20 b can be orientated at a different angle thanthe connecting flange. Other configurations could also be provided ifdesired.

The light emitting region 20 includes a protective layer 25 that can beformed of a material such as silicone and the light emitting region 20may include a layer of a phosphor slurry that acts to convert emittedillumination into a more desirable wavelength of light. More will besaid about possible variations in the protective layer 25 below.

The traces 30 a, 30 b, which are used to power the light emitting region20, can be applied by selectively placing the insulating layer 21 on thedesired surfaces of the base 15 via a powder coating technique. Once theinsulative layer 21 is provided on the desired surfaces of the base 15(such as a top surfaces, one or more side surfaces and a bottomsurface), the base 15 can be cured so that the resulting insulativelayer 21 provides desirable electrical isolation. It should be notedthat the insulative layer 21 can cover substantial portions of the base15 (including the side surfaces and the bottom surfaces of the base 15).Providing additional coverage can help electrically isolate the traces30 a, 30 b from the base and can also help electrically isolate the base15 itself from any exposed metal that might be contained on an adjacentcomponent (such as a heatsink or supporting fixture).

Once the base 15 has the insulative layer 21 selectively applied, traces30 a. 30 b can be formed on the insulative layer 21. FIG. 7, discussedbelow, provides additional information in how an LED module can beformed, including a discussion of the process of forming traces, whichis discussed in greater detail. As can be appreciated, the insulativelayer 21 is applied on the connecting flange 17 so that traces can beformed.

As noted above, the reflective area 22 can omit the insulative layer 21and in an embodiment the reflective area 22 can be polished to aid inlight extraction. LED chips 38 are placed on the reflective area 22 in adesired. As depicted in FIG. 3, for example, a plurality of LEDs areconnected in series to form a LED path 39 and two or more LED paths canbe provided in parallel. Naturally, other circuit patterns can beprovided as desired. It has been determined that it is desirable to havethe LED path 39 configured so that it is actuated by a potential of lessthan 50 volts and more desirable to have the potential needed to actuatethe LED path 39 be less than 25 volts. The use of a lower voltage makesit easier to provide a suitable power supply and also improves creepageand clearance issues.

As can be appreciated from FIG. 4, another embodiment of a LED module10′ is depicted with a light emitting region 20 that includes a base 15′with fastener apertures so that conventional fasteners (such as but notlimited to screw 5) can be used to secure the LED module 10′ inposition. In other embodiments, the base can be sized and shaped so thata fixture holds the LED module in position without the use of separatefasteners. For example, a fixture can be designed with a snap in featurethat allows the module to engage a power source and held in positionwith a clip. In such a situation, the LED module can include athermal-coupling layer (such as a thermal pad or thermal grease) on abottom surface of the base that helps provide improved thermal transferbetween the LED module and a supporting surface.

The conductive traces 30 a, 30 b extend from adjacent the reflectivearea 21 to the connecting flange 17. The connecting flange 17 can besized and configured to mate with a connector 40, where the connectorhas a body 41 that supports terminals that are electrically connect towires 42. The terminals are configured to mate with the anode, cathode31, 32 and thus provide an electrical connection to the light emittingregion 20. The connecting flange 17 can be configured so that it engagesa connector in a polarized manner. It should be noted that in most ofthe depicted embodiments the connecting flange 17 is orientateddifferently than the base 15. The advantage of having the connectingflange orientated/configured in a manner that is different than the baseis that it allows for ease of connecting the connector 40 to the pads onthe connecting flange. For example, the base can have a low profile soas to minimize interference with light output while the connectingflange can be angled in a manner that makes mating to a connector simpleand flexible. It should be noted that while the embodiments in FIGS. 1-4illustrate a connecting flange that is angled in a direction toward theillumination output angle (e.g., similar to that depicted in FIG. 5A),in an alternative embodiment the connecting flange could be angled inthe opposite direction (e.g., similar to that depicted in FIG. 5D). Inaddition, the connecting flange could be offset from the base (asdepicted in FIG. 5B, which show the connecting flange parallel butoffset from the base).

It should be noted that in certain embodiments the connecting flangecould also be aligned parallel with the base of the light emittingregion of the LED module (as depicted in FIG. 5C). Such a configurationwould be suitable, for example, in applications where the fixtureincludes contacts that can engage a flat surface and the module isintended to engage the contacts on one side away from the light emittingregion (in an embodiment the contacts in the fixture could be recessedor shrouded so as to provide a touch safe environment).

FIG. 6 illustrates another embodiment of an LED module 110 withadditional features included. A base 115 includes a flat region 115 athat provides a light emitting region 120, a first curved portion 116,and a connecting flange 117 and a second curved portion 118. As can beappreciated, the light emitting region 120 is positioned in the middleof a curved portion so as to provide a reflective structure that shapesthe light in a focused manner. The base 110 further includes areflection region 121 that primarily is intended to reflect lightemitted from LEDs 140 either out of the LED module or toward the firstand second curved portions 116, 118. As in the above embodiments, thecurved portions can be covered with an insulative layer that allows forelectrical isolation. In an embodiment the insulative layer can be bothelectrically isolated and also have a diffuse highly reflectiveproperty, where the reflective nature of the insulative layer exceeds 90percent.

The LEDs 140, as in the previous embodiments, are connected electricallywith wire bonds 135 in a desired pattern and can be covered with aprotective layer 125 that can include a phosphor layer and/or siliconelayers. The wire bonds 135 connect to conductive traces 130, whichextending along an insulative layer provided on the first curved portion116 and through an aperture in the base 110 to the connecting flange117. Thus, the insulative layer extends from the light emitting region120 to the connecting flange 117. Due to the configuration, the LEDmodule 110 can emit light on first side 114 a of the base and beconnected to power on a second side 114 b of the base 115 and this canbe beneficial in allowing for more desirable fixture designs that placeelectronics and power deliver on one side of the base and the lightemitting region on the other side of the base. As can be appreciated,with the use of a pattern of traces on both sides of the base 115 it ispossible to have components (such as, without limitation, drivers,capacitors, thermistors and fuses) soldered to the traces provided onone side of the base while avoiding any interference with emitted lightthat is provided with LED chips positioned on another side of the base.Naturally, if the base is large enough, additional components and theLED chips could also all be fastened on the same side of the base.

It should be noted that because the base 115 is thermally conductive,the base 115 can be used as a heat sink and, depending on theapplication, may be sufficient to manage the thermal load by itself. Inalternative embodiments, the base 115 can be used as a heat spreader andhelp direct thermal energy to a heat sink.

FIG. 7 illustrates a method that can be used to provide a LED module.First in step 205 a base is formed of a thermally conductive material(such as aluminum or any other desirable thermally conductive metal ormetal alloy and in most cases the base will also be electricallyconductive). As noted above, the base can have a variety of differentshapes depending on the application. Next in step 210 the base isselectively plated with an insulative layer, which could be a powdercoat. In step 215 traces are formed on the insulative layer. In anembodiment this can involve using a laser to activate the insulativelayer in a pattern similar to how laser direct structuring is done onplastic. Once the pattern is formed, the base can be placed in a platingbath so that the pattern is plated through the use of an electrolessprocess. If desired, the thickness of the traces can be furtherincreased, either through additional electroless plating or through theuse of electroplating by applying a charge to the traces and thenplacing the base in a plating bath. Alternatively, the traces can beformed on the insulative layer with an inkjet technique by printingconductive ink directly on the insulative layer. If the traces areformed with an inkjet technique then it may be desirable, depending onthe application and the desired current, to further plate the traces soas to provide a thicker trace that can handle higher current loads andthis preferably will be done using electroplating. It is expected,however, that with an appropriate conductive ink such additional platingwill not be necessary. It should be noted that the traces can be formedon more than one side of the base if desired and can include gaps andcomplicated patterns that allow other electrical components (besides theLED die) to be connected to the traces. As can be appreciated, thetraces will be isolated from any exposed portion of the base and thusthe electroplating operation can be selectively applied.

Once the conductive traces are formed, LED die can be placed on the basein step 220. As can be appreciated, the process of applying die can bedone to a region that is cleaned and polished prior to placement of thedie (e.g., the die can be placed on a reflective area, as discussedabove). In step 225 the LED die are wire bonded together and connectedto the traces. Finally in step 230 the LEDs are covered with aprotective layer that can include a silicone layer and an optionalphosphor slurry layer. Additional layers and filters can be added ifdesired. For example, particular wavelengths of light can be blocked ifthose wavelengths are determined to be undesirable. Additionalcomponents can also be mounted to the base. As can be appreciated,additional components could be attached with solder or a conductiveadhesive.

FIGS. 8-9 illustrate schematic representations of a cross section of anembodiment of a base 315 that can be used in a LED module and the base315 includes a recessed region 319 with wall 318. The recessed region319 includes a reflective area 322 and thus provides a light emittingregion that is between a top surface 315 a and a bottom surface 315 d.The recessed region 319 can be as depicted with a portion of the baseremoved or flattened and thus results in a base where the bottom surface315 d is on a single plane. Alternatively the thickness of the basecould be kept constant and the recession region area just pressed down(which would result in the bottom surface of the base not being on asingle plane). Either way, the recessed region 319 provides a lightemitting area. The recessed region 319 allows LED chips 340 to bepositioned in the reflective area 322 and electrically connected withwire bonds 335. To protect the chips and the wire bonds, a firstsilicone layer 325 a can be placed over the LED chips 340. Then aphosphor layer 325 b can be provided over the first silicone layer. Thephosphor layer 325 b acts to convert light emitted from the LED chipsinto other wavelengths of light. The phosphor layer 325 b can then becovered by an additional silicone layer 325 c. Naturally, additionallayers could be used to provide filtering and/or to provide differentproperties and the depicted embodiment is fairly straightforward. Oneadvantage of the depicted design is that the wall 318 of the recessedregion 319 helps contain layers that are liquid and prevent those layersfrom dissipating or running into adjacent areas. Thus, the recess region319 and the wall 318 together provide containment for the layers duringmanufacturing of the LED module without requiring additional fixtures orsecondary walls.

As noted above, when providing LED chips a number of layers can beprovided. This is generally applicable to any of the LED chip designsdisclosed herein. It is common to use a silicone layer to protect thecomponents and thus it is expected that a protective layer will includeat least something similar to a silicone layer. Additional layers and/orfilters (not shown) can be added above the LED chips depending on theapplication. For example, filters to block certain wave lengths and/oradjust the color of the light could be added. Of course, for anembodiment where the LED chips were configured in a RGB configurationthe phosphor layer and the second silicone layer could be removed as theLED chips would provide the desired output without the need to usephosphor or filters to covert or block certain wavelengths of light.Thus, regardless of the configuration, the use of a recessed regionprovides a number of benefits and can be configured with the appropriatedepth so as to contain the desired layers and the depicted three layerscould be some other number of layers. It should be noted that if desiredthe light emitting region can be highly polished to improve lightextraction and the light emitting region can also be shaped (in additionto or separate from any shaping of other portions of the base) so as tohelp control the shape of light emitted from the light emitting region.

As can be appreciated, the depicted LED modules can provide electricalconnectivity in a compact and cost effective manner. It should be notedthat in an embodiment the base of the LED module can be configured sothat it is large enough such that no additional heat sinks are required.In an alternative configuration, the base can be configured to thermallycouple to a heat sink and thus act more as a heat spreader.

The disclosure provided herein describes features in terms of preferredand exemplary embodiments thereof. Numerous other embodiments,modifications and variations within the scope and spirit of the appendedclaims will occur to persons of ordinary skill in the art from a reviewof this disclosure.

We claim:
 1. A method of forming a component module, comprising:providing a base, the base being electrically conductive; providing aninsulative layer on the base, wherein a first area is substantially freeof the insulative layer; providing a first trace and a second trace onthe insulative layer, the first and second traces extending fromadjacent the first area; positioning a die on the first area;electrically connecting the die to the first and second traces; andproviding a protective layer over the die.
 2. The method of claim 1,wherein the first area is recessed.
 3. The method of claim 2, whereinthe providing of the first and second traces includes providing two padson a connecting area, one of the two pads electrically connected to thefirst trace and the other of the two pads electrically connected to thesecond trace.
 4. The method of claim 3, wherein the forming of thetraces comprises placing a conductive ink directly on the insulativelayer.
 5. The method of claim 3, wherein the forming of the tracescomprises forming a pattern on the insulative layer with a laser andthen placing the base in a plating bath so that a conductive layer formson the pattern.
 6. The method of claim 1, wherein the base comprises athermally conductive material.
 7. The method of claim 1, wherein thebase comprises a metal alloy.
 8. The method of claim 1, whereinproviding an insulative layer on the base comprises selectively platingthe base.
 9. The method of claim 8, wherein the insulative layercomprises a powder coat.
 10. The method of claim 1, wherein theinsulative layer comprises a plastic.
 11. The method of claim 10,wherein providing a first trace and a second trace on the insulativelayer comprises performing laser direct structuring on the plastic. 12.The method of claim 1, wherein providing a first trace and a secondtrace on the insulative layer comprises printing conductive ink on theinsulative layer.
 13. The method of claim 12, wherein providing a firsttrace and a second trace on the insulative layer comprises printingconductive ink on the insulative layer and then plating usingelectroplating.
 14. The method of claim 1, wherein the base has a topsurface and a bottom surface and at least one of the first trace and thesecond trace extends from the top surface to the bottom surface.
 15. Themethod of claim 1, wherein the base has a first surface and a secondsurface that are not co-planar and at least one of the first trace andthe second trace extends from the first surface to the second surface.16. The method of claim 1, wherein the base has a surface, at least aportion of the surface not being planar and at least one of the firsttrace and the second trace extending across the non-planar portion ofthe surface.